1. Field of the Invention
The present invention relates in general to electrically-driven cooling systems used with internal combustion engines and the like for automotive vehicles and the like, and in particular to electrically-driven, air-assisted cooling systems for use with internal combustion engines in automotive applications.
2. Description of Related Art
In conventional water pump systems used on automobiles, a drive belt and pulley are used to provide the drive rotation to the coolant pump shaft. The coolant may be of any suitable type, such as the commonly used mixture of water and anti-freeze. A gear or chain drive is sometimes used instead of a belt and pulley. A double set of bearings are typically provided in the pump casing to resist the large external side load forces generated by such a pulley, gear or chain drive. As is well known in the art, when these side load forces are considered, the overall forces experienced by the pump shaft are inherently unbalanced. On account of the unbalanced force vector to the pump shaft, it is necessary to suitably strengthen the pump assembly, pump shaft and its ball bearings to handle expected loads and overloads. This adds to the cost and weight of the coolant pump.
The use of the aforementioned side-loaded drive systems also create an additional expense in that the crank shaft or cam shaft of the vehicle must be extended through the engine block wall so that the master drive pulley or gear can be mounted on the shaft. The master drive pulley and belt or gears also add expense and weight to the vehicle's power plant. Passing the crank shaft or cam shaft through the engine block wall also requires that appropriate measures be taken to seal the shaft bearing from environmental contamination such as moisture, dirt and dust, or acidic or salty water sprayed up from road surfaces. A common failure mode for water pumps is the failure or wear of the water pump bearing. Severe bearing wear often results in damage to the flexible coolant face seal assembly, which allows coolant to escape from the engine's cooling system, thus presenting further problems. If the pump bearings did not fail in the first place, many such failures of the flexible face seal assembly could be avoided, along with the resultant loss of engine coolant and destruction of the pump shaft on account of scoring and galling.
Accordingly, it would be very beneficial to provide a direct drive water pump system which solves most, if not all, of the foregoing problems. "Direct-drive" as referred to herein means a drive system that avoids applying external side loads to the pump shaft and bearing set which supports the pump shaft. It would also be useful to eliminate the need to extend the crank shaft or cam shaft outside of the engine block to provide the rotational power required to drive the coolant pump. It would also be desirable to provide a new design for a coolant pump system which can be easily adapted to handle different pumping requirements. It would also be useful to drive both the coolant pump and radiator cooling fan with the same direct-drive system. Finally, it would be beneficial to provide the direct-drive water pump system with an air-assisted cooling fan which reduces the amount of electricity necessary to drive the motor which turns the fan.
In using direct-drive systems as well as virtually all other types of cooling systems a problem arises in that unnecessary electrical energy is expended in driving the cooling fan. While the direct-drive cooling system solves many of the problems associated with water pumps failures, the system still requires electrical energy to operate the motor which drives the cooling fan. This electrical energy however, could be more beneficially spent on other electrical systems throughout the automobile.
In light of the foregoing problems, and in order to fulfill one or more of the foregoing objects and desires, there is provided an air-assisted, electric drive cooling system for use with an automotive vehicle. The system comprises a coolant pump for forcing the circulation of coolant, an electric motor for driving the pump, an air-assisted, electric drive cooling system which reduces the amount of electrical energy utilized in operating the cooling fan and a water pump.
It is another object of the present invention to provide an air-assisted, electric drive cooling system which gives rise to improved auto emissions since the engine would remain at a more constant temperature and therefore burn fuel more efficiently.
It is a further object of the present invention to provide an air-assisted electric drive cooling system which improves the water seal life of the water pump used in the electric drive system by running at lower speeds and by avoiding side loads.
Yet another object is to improve vehicle fuel efficiency and reduce automobile emissions.